In many industries, it is often desirable to extract meaningful information from images to provide an understanding of the objects depicted in the images. For example, aircraft such as unmanned aerial vehicles (UAVs) or other remotely piloted vehicles, autonomous airborne vehicles or the like, may carry cameras for capturing aerial images for inspection, survey and surveillance of objects depicted in the images. These aircraft often also geo-register aerial images with the geographic locations of objects of interest depicted in the images, many employing cameras equipped with Global Positioning System (GPS) receivers to determine geographic location. But because of the high altitude and speed of the aircraft, the geographic location provided by many of these GPS receivers is often inaccurate, some resulting in a shift in geographic location of an object by as much as 10-20 kilometers compared to a ground survey of the object. It is generally desirable to correct the error in geo-registration of aerial images for accurate inspection, survey and surveillance, but it is difficult to accomplish.
There are approaches to more accurately geo-register aerial images, including those that employ ground control markers. Ground control markers are usually black-white check pattern, painted on paper cardboard, metal sheet or pavement on the ground. The design of markers allows operators to see them with ease from the aerial capture, and input them in a geo-registration tool. But ground control markers require a lot of manual input. A person needs to place the marker at a proper location and record the GPS data. The person also needs to locate the aerial markers after the data capture. It is clearly an expensive and slow process required for each flight.
Other approaches employ image stereo matching in which an oblique image is registered to a previously generated two-dimensional, geo-referenced image. This is also sometimes called geo-registration feature matching. The drawback of this approach is that an already geo-registered reference image is required, which is not always available or easy to obtain.
Therefore it would be desirable to have a system and method that takes into account at least some of the issues discussed above, as well as other possible issues.